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Amazon·Research Scientist·Onsite - Multi Round·Senior

Senior
Jun 2026

Summary

Applied Scientist loop at Amazon with a round built entirely around an ambiguous, under-defined business problem. No coding, no system design slides, just a vague prompt and a lot of silence while you figure out what to even ask.

Questions Asked (4)

Q1

Here is a vague business problem. Walk me through how you would approach it.

Adaptability & AmbiguityProduct Sense & IdeationProduct Analytics & Metrics
Author's notes

The silence after the prompt is genuinely uncomfortable.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the problem to define scope and success metrics, then structure your approach using a hypothesis-driven method. Emphasize iterative learning, data-driven decisions, and alignment with business goals.

Pro tip: Demonstrate scientific rigor by proposing testable hypotheses and designing experiments, while showing flexibility to pivot based on findings. Highlight how you would leverage Amazon's customer obsession and data culture.

1. Clarify the Problem

Ask questions to understand the business context, stakeholders, constraints, and what success looks like. Define the problem statement and key metrics.

2. Form Hypotheses

Based on available data and domain knowledge, generate testable hypotheses about root causes or potential solutions. Prioritize them by impact and feasibility.

3. Design Experiments

Outline experiments or analyses to test hypotheses, including data sources, methods, and success criteria. Consider quick wins and long-term investigations.

4. Analyze and Iterate

Execute experiments, analyze results, and draw conclusions. Iterate on hypotheses or experiments based on findings, maintaining a feedback loop.

5. Recommend and Implement

Translate findings into actionable recommendations, considering business impact and scalability. Propose next steps for implementation and monitoring.

Key Points to Mention

  • Customer obsession: tie the problem back to customer impact
  • Data-driven decision making: use metrics and experiments
  • Hypothesis-driven approach: start with assumptions to test
  • Iterative process: be ready to pivot based on learnings
  • Stakeholder alignment: communicate with cross-functional teams
  • Scalability and long-term impact: consider broader implications

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.

Q2

How would you define success for this problem, and what metrics would you use to measure it?

Product Analytics & MetricsA/B Testing & Experimentation
Author's notes

I fumbled around for a bit before landing on anything concrete.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the problem's business objective and how it aligns with Amazon's leadership principles, especially Customer Obsession. Then define success in terms of both customer impact and business outcomes, and propose a balanced set of metrics (e.g., primary, secondary, guardrail) that can be measured via experiments. Emphasize the importance of statistical rigor and iterative learning.

Pro tip: Tie your metrics to a north star metric that directly reflects customer value, and mention how you would use A/B testing to validate causality and avoid vanity metrics.

1. Clarify the problem and business goal

Ask questions to understand the problem's context, the target customer, and the desired business impact. This ensures your definition of success aligns with stakeholder expectations.

2. Define success criteria

Articulate what success looks like in terms of customer and business outcomes, such as increased engagement, revenue, or satisfaction. Make it specific and measurable.

3. Select metrics

Choose a primary metric that directly measures the desired outcome, supported by secondary metrics for depth and guardrail metrics to monitor unintended consequences.

4. Plan measurement and experimentation

Describe how you would measure these metrics, including experimental design (e.g., A/B test), sample size, and duration. Mention statistical significance and practical significance.

5. Iterate and refine

Explain how you would use initial results to learn and adjust metrics or hypotheses, emphasizing continuous improvement and learning from failures.

Key Points to Mention

  • Alignment with Amazon's Leadership Principles (e.g., Customer Obsession, Dive Deep)
  • Primary, secondary, and guardrail metrics
  • North star metric and its connection to customer value
  • A/B testing and statistical significance
  • Avoiding vanity metrics and ensuring metrics are actionable
  • Iterative experimentation and learning from failures

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.

Q3

What are two or three plausible hypotheses for why this problem exists, and how would you distinguish between them experimentally?

A/B Testing & ExperimentationAdaptability & AmbiguityRoot Cause Analysis
Author's notes

This is where having a real worked example from past projects saves you.

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AI HintsAI Generated

Suggested Approach

Start by clearly stating the problem and then propose two or three distinct, testable hypotheses that could explain it. For each hypothesis, outline a specific experiment that would provide evidence for or against it, focusing on how you would isolate variables and measure outcomes. Emphasize the importance of falsifiability and practical constraints in experimental design.

Pro tip: Demonstrate scientific maturity by acknowledging that the most likely explanation may be a combination of factors, and propose a sequential testing strategy that starts with the cheapest, fastest experiments to narrow down the possibilities.

1. Define the problem and context

Briefly restate the problem and its impact, ensuring alignment with business goals. Mention any existing data or observations that inform the hypotheses.

2. Generate plausible hypotheses

Propose 2-3 distinct, testable hypotheses that could explain the problem. Ensure they are mutually exclusive or can be tested independently.

3. Design experiments to test each hypothesis

For each hypothesis, describe a specific experiment, including variables, controls, metrics, and success criteria. Prioritize experiments by feasibility and potential impact.

4. Explain how to distinguish between hypotheses

Discuss how the results of each experiment would support or refute each hypothesis, and how you would interpret conflicting evidence.

5. Address practical considerations

Mention potential challenges such as sample size, confounding variables, and ethical constraints, and how you would mitigate them.

Key Points to Mention

  • Falsifiability: Each hypothesis must be testable and potentially disprovable.
  • Experimental design: Use of control groups, randomization, and blinding to reduce bias.
  • Metrics: Define clear, quantifiable success metrics for each experiment.
  • Prioritization: Start with low-cost, high-information experiments to quickly narrow down hypotheses.
  • Confounding variables: Identify and control for external factors that could affect results.
  • Iterative approach: Be prepared to refine hypotheses based on initial results and run follow-up experiments.

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.

Q4

If you ran an experiment and saw improvement on your offline metric but no lift in the online A/B test, what would you do?

A/B Testing & ExperimentationTechnical Trade-offs
Author's notes

Decent question.

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AI HintsAI Generated

Suggested Approach

Start by acknowledging the discrepancy as a common and valuable learning opportunity, then systematically diagnose potential causes across offline-online gaps, experiment design, and metric validity. Emphasize a structured, data-driven approach that prioritizes understanding the root cause before deciding on next steps, and highlight the importance of aligning offline metrics with online business objectives.

Pro tip: Demonstrate scientific rigor by proposing to validate the offline metric's predictive power through historical experiments or by running a holdback to measure long-term effects, showing you think beyond immediate A/B results.

1. Verify Experiment Integrity

Check for implementation issues, sample ratio mismatch, or instrumentation errors that could invalidate the online test. Ensure the experiment was properly powered and ran for a sufficient duration.

2. Analyze Offline-Online Gap

Investigate differences between offline and online environments, such as data distribution shifts, feature availability, or user behavior changes. Assess whether the offline metric is a reliable proxy for online success.

3. Evaluate Metric Sensitivity and Business Impact

Determine if the online metric is sensitive enough to detect the expected effect size, and whether the offline improvement translates to meaningful business impact. Consider alternative online metrics that might capture the change.

4. Conduct Deep-Dive Analysis

Segment the online results by user cohorts, devices, or geographies to uncover heterogeneous treatment effects. Use qualitative methods like user surveys or session replays to understand behavioral drivers.

5. Decide and Iterate

Based on findings, decide whether to iterate on the model, adjust the offline metric, redesign the online experiment, or abandon the change. Document learnings to improve future offline-online correlation.

Key Points to Mention

  • Sample Ratio Mismatch (SRM) and other validity checks
  • Offline-online metric correlation and proxy validity
  • Statistical power and minimum detectable effect (MDE)
  • Heterogeneous treatment effects and segmentation
  • Long-term holdback or counterfactual analysis
  • Iterative experimentation and learning culture

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.